Physical properties of niobium

Niobium is an element of the V subgroup of the periodic table. Its symbol is Nb. Its atomic number is 41. It is one of high melting point metals. Silver has a melting point of 2,469,410°C and a boiling point of 4,840°C. It is classified as a refractory metal. Niobium itself is steel gray, hard and ductile. The density of niobium is 8.66g/cm3 and the atomic radius is 0.145nm. Under the action of external force, the stamping and forming of metal materials uses pressure rolling mills, spinning machines or other equipment to apply pressure to the plates to plastically deform the materials to obtain parts of different shapes and sizes. Crystal form. Niobium has a body-centered cubic crystal form, the structure type is A2, has 48 slip systems, and the ductility-brittle transition temperature (DBTT) is very low, less than 150℃, and has excellent plastic deformation ability. It is easy to produce into various sizes and shapes of product. Taking the niobium sheet as an example, the thinnest niobium foil can be rolled to 0.01mm, and the 0.1mm niobium strip can be stamped into a cup with a diameter of 2mm using a die, which is used as the cathode material of the LED light source.

Niobium is a refractory metal material with a high melting point. Niobium and niobium alloys are often used in high temperature conditions, and the application temperature is often above 1000 ℃. Therefore, the thermal conductivity and thermal expansion coefficient of niobium at high temperature are very important for the actual application of materials. Have a great impact. As the temperature increases, the thermal conductivity of niobium increases almost proportionally. The coefficient of thermal expansion of niobium can be divided into two stages with temperature changes. Above 800°C, the coefficient of thermal expansion increases suddenly and gradually increases as the temperature rises.